Congestive heart failure (CHF) is a leading cause of death in the United States. CHF occurs when the heart is unable to adequately supply enough blood to maintain a healthy physiological state. CHF can be treated by drug therapy, or by an implantable medical device (IMD) such as for providing cardiac electrostimulation therapies, including resynchronization therapy (CRT) to correct cardiac dyssynchrony within a ventricle or between ventricles.
The IMD can chronically stimulate excitable tissues or organs, such as a heart, to treat abnormal cardiac rhythms or to help improve cardiac performance in a patient with CHF. Such ambulatory medical devices can have at least first and second electrodes that can be positioned within the heart or on a surface of the heart for contacting the cardiac tissue. The electrodes can be electrically coupled to an electronics unit such as a pulse generator, such as via a lead, and can be used to deliver one or more electrostimulations to the heart, such as to restore or to improve the normal heart function.